This invention relates to fungi that are useful for controlling infestations of Coleoptera, particularly Diaprepes abbreviatus. 
A temperate climate provides a favorable environment for year-round cultivation of a variety of horticultural crops. The same mild conditions and the constant availability of host plants, however, also encourage the proliferation of herbivorous insects, including Coleoptera such as beetles and weevils. Significant crop damage will result if the population of these insects is not kept under control.
One such economically important pest is the sugar cane rootstalk borer Coleoptera, Diaprepes abbreviatus (Insecta: Coleoptera: Curculionidae). Diaprepes is a polyphagous insect that attacks over 200 varieties of plants, including commercial crops such as citrus, potato, cotton, pepper, and a number of field-grown nursery species.
The presence of Diaprepes, which is native to the Caribbean, was first documented in the U.S. in 1964 at Apopka, Orange County, Fla. Woodruff, Ent. Cir. 30 (Fla. Dept. Agr. and Consumer Serv., Div. Plant Ind.), 2, 1964. Since its first detection, established populations of the insect have been identified in most of Florida. Hall, Fla. Entomol. 78, 1173-82, 1997.
Adult Diaprepes feed on leaves of host plants and, depending on the plant type, can cause extensive damage to the foliage, causing a reduction in fruit yield or plant death.
Females lay egg clusters of approximately 100 eggs in the plant canopy. The females lay their eggs between two leaves, which they glue together to avoid predation. The glue is a mixture of long chain carbohydrates and proteins, which dries to produce a water insoluble matrix. This behavior produces a constant humidity microclimate that helps the development of the eggs. After maturation (7 to 10 days after laying), the larvae chew through the egg casings and the glue matrices and fall to the ground, where they tunnel into the soil. This subterranean larval stage is the most damaging stage to citrus trees. The larvae feed on citrus roots, which causes a reduction in fruit yield and will eventually destroy the tree.
Damage caused by the insect feeding on citrus has been estimated at $75 million per year. Diaprepes Task Force Report, Fla. Dept. Agr. and Consumer Serv., Div. Plant Ind., Bureau of Pest Eradication and Control, 1995. Damage increases each year as the coleopteran infestation spreads. This pest has affected the citrus industry in Puerto Rico to such an extent that citrus is no longer grown commercially. Due to the lack of suitable control measures, including chemical pesticides, the Diaprepes population in Florida is on the rise and poses a serious threat not only to Florida agriculture, but also to agricultural industries in other states.
Entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana capable of infecting Diaprepes abbreviatus larvae have been isolated and are commercially available. Quintela and McCoy, J. Econ. Entomol. 26, 1173-82, 1997. The fungi are primarily used as soil amendments to combat larvae already in the soil; neither of these fungi has been shown to grow on the Diaprepes eggs. The ability of these fungi to achieve significant control of the Diaprepes population is hampered by the fact that, depending on the soil titer, the Diaprepes larvae might not come into contact with the fungi. There is, therefore, a need in the art for biological reagents that can be more effectively used to combat Diaprepes infestations, as well as infestations of other Coleoptera.
It is an object of the present invention to provide compositions and methods for controlling coleopteran infestations of host plants. These and other objects of the invention are provided by one or more of the embodiments described below.
One embodiment of the invention is a purified preparation of a fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30399, 30401, 30402, 30403, and 30400 and mixtures thereof.
Another embodiment of the invention is a composition comprising a fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30399, 30401, 30402, 30403, and 30400 and spores thereof.
Still another embodiment of the invention is a method of controlling a coleopteran infestation of a host plant. The host plant is contacted with a composition comprising an egg mass pathogen. The egg mass pathogen is selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30401, 30402, 30403, and 30400 and spores thereof. The egg mass pathogen thereby infects a coleopteran egg.
Yet another embodiment of the invention is a method of controlling a coleopteran infestation of a host plant. The host plant is contacted with a composition comprising a larval pathogen selected from the group consisting of a fungus identified with NRRL Accession No. 30399 and spores thereof. The larval pathogen infects a coleopteran larva.
Even another embodiment of the invention is a purified preparation of a first fungus or a spore thereof, wherein the first fungus has all the identifying characteristics of a second fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30399, 30401, 30402, 30403, and 30400.
Another embodiment of the invention is a purified preparation of a first fungus or a spore thereof, wherein the first fungus has all the characteristics for infection of a coleopteran egg of a second fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30401, 30402, 30403, and 30400.
Still another embodiment of the invention is a purified preparation of a first fungus or a spore thereof, wherein the first fungus has all the characteristics for infection of a coleopteran larva of a second fungus identified with NRRL Accession No. 30399.
Yet another embodiment of the invention is a composition comprising a first fungus or a spore thereof, wherein the first fungus has all the identifying characteristics of a second fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30399, 30401, 30402, 30403, and 30400.
Even another embodiment of the invention is a composition comprising a first fungus or a spore thereof, wherein the first fungus has all the identifying characteristics for infection of a coleopteran egg of a second fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30401, 30402, 30403, and 30400.
Another embodiment of the invention is a composition comprising a fungus or a spore thereof, wherein the fungus has all the identifying characteristics for infection of a coleopteran larva of a second fungus identified with NRRL Accession No. 30399.
A further embodiment of the invention is a method of controlling a coleopteran infection of a host plant. The host plant is contacted with a composition comprising a first fungus or a spore thereof. The first fungus has all the identifying characteristics for infection of a coleopteran egg of a second fungus selected from the group consisting of fungi identified with NRRL Accession Nos. 30397, 30398, 30401, 30402, 30403, and 30400.
Still another embodiment of the invention is a method of controlling a coleopteran infection of a host plant. The host plant is contacted with a composition comprising a first fungus or a spore thereof, wherein the first fungus has all the identifying characteristics for infection of a coleopteran larva of a second fungus identified with NRRL Accession No. 30399.
Another embodiment of the invention is a purified preparation of a fungus or a spore thereof. The fungus (1) is capable of infecting a coleopteran egg, whereby infection results in destruction of the egg; (2) grows rapidly on the coleopteran egg; (3) can be propagated using conventional fermentation technology; (4) sporilates easily; (5) is not pathogenic to a host plant; and (6) is not pathogenic toward beneficial insect species.
Even another embodiment of the invention is a composition comprising a fungus or a spore thereof. The fungus (1) is capable of infecting a coleopteran egg, whereby infection results in destruction of the egg; (2) grows rapidly on the coleopteran egg; (3) can be propagated using conventional fermentation technology; (4) sporilates easily; (5) is not pathogenic to a host plant; and (6) is not pathogenic toward beneficial insect species.
A further embodiment of the invention is a purified preparation of a fungus or a spore thereof. The fungus (1) is capable of infecting a coleopteran larva, whereby infection results in death of the larva; (2) can be propagated using conventional fermentation technology; (3) sporilates easily; (4) is not pathogenic to a host plant; and (5) is not pathogenic toward beneficial insect species.
Yet another embodiment of the invention is a composition comprising a fungus or a spore thereof. The fungus (1) is capable of infecting a coleopteran larva, whereby infection results in death of the larva; (2) can be propagated using conventional fermentation technology; (3) sporilates easily; (4) is not pathogenic to a host plant; and (5) is not pathogenic toward beneficial insect species.
The invention thus provides particular fungi that are pathogenic to Coleoptera. These fungi can be used to control coleopteran infestations of a wide variety of host plants.